Although the egg represents an outstanding nutritional food, and a food that people enjoy eating, especially as part of the breakfast in the morning, the fact that it is one of the richest foods in cholesterol and saturated fats has forced an enormous number of people to avoid consuming eggs.
A large number of solutions have been proposed to answer this problem, some more and some less successful.
A highly compromised solution, which has been found commercially attractive, has been the one according to which the egg yolk is removed and substituted usually by the equivalent amount of egg white, which may also be simulated with a yellow-orange food-colorant and small quantities of other adjuncts improving desired properties of the simulated egg. Since this type of simulated egg has the consistency and appearance of mixed egg-whites with egg-yolks, it can only be used as "scrambled eggs", or omelette, or more generally in cooking recipes requiring mixed egg-yolks with egg-whites. This is a serious draw-back because it does not provide people with the option to have a cholesterol-free fried or a poached egg having an egg-yolk in a separate phase from the white. An egg with the yolk in a separate phase from the white is highly desirable to a large number of people.
Liquid egg-products without a separate phase of the yolk from the white are the subject of a number of U.S. Patents. Representative ones, among others, are U.S. Pat. Nos. 3,911,144, 3,987,212, 4,103,038, and 4,296,134.
U.S. Pat. No. 3,804,951 describes an egg-extender composition consisting essentially of an interrupted aqueous gel product containing kappa-carrageenan, xanthan gum, locust gum, and potassium citrate and water.
A method of preparing an egg-yolk substitute and resulting products from its use is described in U.S. Pat. No. 3,864,500. The invention of this patent is directed mainly to the addition of the resulting egg-yolk in recipes of products such as cakes, cookies, and the like, so that shaping and preserving the yolk in liquid egg-white is not important.
U.S. Pat. Nos. 5,073,399, 5,149,561, and 5,151,293, all three of which are incorporated herein by reference, describe simulated eggs having the yolk and the egg-white together but in separate phases. The yolks of these eggs are non-flowable at room temperature, but they liquify at cooking temperatures and remain flowable at serving temperatures for consumption, in the form of "sunny-side-up" or "over-easy" versions.
U.S. Pat. No. 5,192,566 also discloses a whole egg analogue wherein the yolk analogue is treated to form a membrane on its outer surface. The yolk analogue with its attendant membrane is combined with natural egg white, treated egg white, or an egg white analogue to form the whole egg analogue.
U.S. Pat. No. 3,510,315 describes a solid prepared egg product, wherein a cooked real egg-yolk containing a proteolytic enzyme is surrounded with cooked egg-white containing a water binding material.
U.S. Pat. No 3,640,732 describes a simulated cooked egg approximating a boiled, poached or fried hen's egg, wherein the yolk may contain water, vegetable oil, protein, a gel former with a setting agent, and colorant, while the white portion contains similar ingredients without the colorant.
U.S. Pat. No. 3,843,825 provides a method for making a product resembling a hard boiled egg cut in half with the yolk removed, by appropriately molding and coagulating egg-white.
U.S. Pat. No. 4,046,922 discloses a shelf-stable cooked, simulated egg comprising specified amounts of egg-solids, edible water absorbing hydrocolloid, a high protein binding agent, water, and either sugar, sugar equivalents, or mixtures thereof.
U.S. Pat. No. 3,941,892 discloses an egg product made by molding a low cholesterol egg-yolk portion of critical formulation together with an egg-white portion, and subjecting the egg to freezing. In the preferred embodiment, the mold employed in forming the egg product is employed as the package.
U.S. Pat. No. 4,103,040 discloses a wet egg-yolk which is combined with edible oil by high energy, high shear mixing, so that the cholesterol is extracted by the oil from the egg-yolk. At the same time the ratio of the polyunsaturated fats to the saturated fats increases. The yolk, after separation from the oil can become a constituent of various egg-products.
U.S. Pat. No. 4,409,249 describes a method according to which high energy agitation is applied to coagulated and uncoagulated egg-white portion to form a homogeneous, aerated egg white dispersion. The egg-white dispersion is then assembled with processed egg-yolk and the assembly is frozen.